blob: 73eb622e7663d9ba11960aff92baecdd88536721 [file] [log] [blame]
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ASSEMBLY__
#include <linux/compiler.h>
#include <uapi/linux/time.h>
#include <uapi/linux/types.h>
#include <uapi/asm-generic/errno-base.h>
#include <vdso/bits.h>
#include <vdso/clocksource.h>
#include <vdso/ktime.h>
#include <vdso/limits.h>
#include <vdso/math64.h>
#include <vdso/processor.h>
#include <vdso/time.h>
#include <vdso/time32.h>
#include <vdso/time64.h>
#include <asm/vdso/data.h>
struct arch_vdso_data {};
#define VDSO_BASES (CLOCK_TAI + 1)
#define CS_HRES_COARSE 0
#define CS_RAW 1
#define CS_BASES (CS_RAW + 1)
* struct vdso_timestamp - basetime per clock_id
* @sec: seconds
* @nsec: nanoseconds
* There is one vdso_timestamp object in vvar for each vDSO-accelerated
* clock_id. For high-resolution clocks, this encodes the time
* corresponding to vdso_data.cycle_last. For coarse clocks this encodes
* the actual time.
* To be noticed that for highres clocks nsec is left-shifted by
* vdso_data.cs[x].shift.
struct vdso_timestamp {
u64 sec;
u64 nsec;
* struct vdso_data - vdso datapage representation
* @seq: timebase sequence counter
* @clock_mode: clock mode
* @cycle_last: timebase at clocksource init
* @mask: clocksource mask
* @mult: clocksource multiplier
* @shift: clocksource shift
* @basetime[clock_id]: basetime per clock_id
* @offset[clock_id]: time namespace offset per clock_id
* @tz_minuteswest: minutes west of Greenwich
* @tz_dsttime: type of DST correction
* @hrtimer_res: hrtimer resolution
* @__unused: unused
* @arch_data: architecture specific data (optional, defaults
* to an empty struct)
* vdso_data will be accessed by 64 bit and compat code at the same time
* so we should be careful before modifying this structure.
* @basetime is used to store the base time for the system wide time getter
* VVAR page.
* @offset is used by the special time namespace VVAR pages which are
* installed instead of the real VVAR page. These namespace pages must set
* @seq to 1 and @clock_mode to VDSO_CLOCKMODE_TIMENS to force the code into
* the time namespace slow path. The namespace aware functions retrieve the
* real system wide VVAR page, read host time and add the per clock offset.
* For clocks which are not affected by time namespace adjustment the
* offset must be zero.
struct vdso_data {
u32 seq;
s32 clock_mode;
u64 cycle_last;
u64 mask;
u32 mult;
u32 shift;
union {
struct vdso_timestamp basetime[VDSO_BASES];
struct timens_offset offset[VDSO_BASES];
s32 tz_minuteswest;
s32 tz_dsttime;
u32 hrtimer_res;
u32 __unused;
struct arch_vdso_data arch_data;
* We use the hidden visibility to prevent the compiler from generating a GOT
* relocation. Not only is going through a GOT useless (the entry couldn't and
* must not be overridden by another library), it does not even work: the linker
* cannot generate an absolute address to the data page.
* With the hidden visibility, the compiler simply generates a PC-relative
* relocation, and this is what we need.
extern struct vdso_data _vdso_data[CS_BASES] __attribute__((visibility("hidden")));
extern struct vdso_data _timens_data[CS_BASES] __attribute__((visibility("hidden")));
* The generic vDSO implementation requires that gettimeofday.h
* provides:
* - __arch_get_vdso_data(): to get the vdso datapage.
* - __arch_get_hw_counter(): to get the hw counter based on the
* clock_mode.
* - gettimeofday_fallback(): fallback for gettimeofday.
* - clock_gettime_fallback(): fallback for clock_gettime.
* - clock_getres_fallback(): fallback for clock_getres.
#include <asm/vdso/compat_gettimeofday.h>
#include <asm/vdso/gettimeofday.h>
#endif /* !__ASSEMBLY__ */
#endif /* __VDSO_DATAPAGE_H */